Cleaning and Hulling

At the processing plant, the rice is cleaned and hulled. At this point, brown rice needs no further processing. If white rice is desired, the brown rice is milled to remove the outer bran layers. Hulling is the process to remove the hull from the kernel.

Hulling can be done by hand by rolling or grinding the rough rice between stones. However, more often it is processed at a mill with the help of automated processes.

The process of mechanical hulling

• The rough rice is first cleaned by passing through a number of sieves that sift out the debris. Blown air removes top matter.
• Once clean, the rice is hulled by a machine that mimics the action of the hand held stones.
• The shelling machine loosens the hulls from the rice. About 80-90% of the kernel hulls are removed during this process.
• From the shelling machine, the grains and hulls are conveyed to a stone reel that aspirates the waste hulls and moves the kernels to a machine that separates the hulled from the unhulled grains.
• By shaking the kernels, the paddy machine forces the heavier unhulled grains to one side of the machine, while the lighter weight rice falls to the other end.
• The unhulled grains are then siphoned to another batch of shelling machines to complete the hulling process.
• Hulled rice grains are known as brown rice.